A. Field of the Invention
The present invention relates generally to the field of grounds care systems and implements and, more particularly, to a drop spreader for granular material that is configured for attachment to the rear chassis region of a lawn mower, such as a zero turn lawn mower.
B. Description of the Prior Art
Granular material spreaders are used in a wide variety of applications both by individual consumers and in industrial ground keeping applications. They are commonly used for the distribution of fertilizers and insecticides but may also be used to distribute such things as top soil or sand in top dressing applications, as well as for distribution of ice control materials on walkways around buildings and landscaping. Such spreaders may be generally classified in two types, drop spreaders and broadcast or spinner spreaders.
Drop spreaders of the stand alone or towed type are well known in the art and typically include a hopper having a plurality of discharge openings or apertures formed in a bottom through which the granular material is discharged under the action of gravity. In addition, many drop spreaders have an adjustable door or gate which can be adjusted for selectively obscuring the discharge openings in the hopper, thereby restricting or interrupting the amount of granular material discharged. Furthermore, some drop spreaders also incorporate an agitator or other device for mechanically churning the granular material located above the discharge openings, thereby improving the material flow of material through the openings.
While such drop spreaders have performed satisfactorily in many applications over the years, they have not typically been associated with a lawn mowing device so that, for example, fertilizer is being distributed at the same time the area of grass is being mowed. In some cases, drop spreaders have been towed behind or pushed in front of various types of ground care mechanized equipment, but it the arrangement of the equipment did not readily indicate the path over which the fertilizer was spread or the degree of coverage obtained.
In contrast to drop spreaders, broadcast or spinner type spreaders include a rotating member for centrifugally dispersing or “casting” the material out away from the spreader. The amount and concentration of material disbursed is controlled by metering the amount of material delivered to the rotating member and/or adjusting the speed of the rotating member. Unfortunately, the typical broadcast spreader has not proven to be particularly accurate in delivering a precise amount of granular material over a particular area and, in general, is less accurate than the drop style spreader.
In addition to the above described different categories of spreaders, the prior art devices used as fertilizer/chemical/seed spreaders have primarily been separated into two entirely separate lines of equipment. In the first type of device, mowing and fertilizing are achieved as two separate tasks, requiring a separate spreader and mower. This component arrangement is essentially a repetitive, time consuming process in which the operations must be performed as two separate steps and not simultaneously.
In the case of the second type of device, some type of add-on configuration was utilized. In some instances, this type of device involved the integration of the spreader with the lawnmower, with the fertilizer being fed through the blade housing and distributed primarily by the action of the lawnmower blade while turning. This type arrangement has the disadvantage that it allows for extensive contact between the fertilizer and the mower or blade assembly, thereby allowing the possibility that corrosive reactions could occur between the chemicals being spread and the metallic surfaces of the lawnmower. Also, the action of the blades in this type of arrangement may provide less than adequate spreading of the fertilizer since the lawnmower was designed as a mowing device, rather than as a spreading device. It is also difficult to observe the path and quantity of the material being discharged where the fertilizer is being fed through the interior of the lawnmower body.
Other attempts at combining spreaders with lawn mowers have relied on the vibration and swinging movements of the spreader body itself to provide for spreading of the contents of the hopper. This type of system has obvious flaws in that the spread of the fertilizer is very erratic and uneven, and little control over the fertilizing process is possible.
The shortcomings of the prior art show the need for a spreader which is adaptable for mounting on a riding lawn mower, preferably of the zero turn radius type. The spreader should be easily removable from the riding lawn mower, for example, for maintenance or storage or to allow transfer from one mower to another. The system should also allow for the control of the rate at which fertilizer is spread and prevent any significant contact between the fertilizer and the lawnmower to prevent corrosive/chemical attack of the lawnmower. The spreader/lawn mower combination should allow the operator to easily observe the amount of granular material being distributed and see the path over which the distribution is taking place.
It is an aim of the present invention to meet these shortcomings of the prior art as described above, as will be set forth in greater detail in the written description which follows.